Initial revision

git-svn-id: http://php-reader.googlecode.com/svn/trunk@2 51a70ab9-7547-0410-9469-37e369ee0574

src/Reader.php

@@ -0,0 +1,182 @@
+<?php
+/**
+ * $Id$
+ *
+ *
+ * Copyright (C) 2006, 2007 The Bearpaw Project Work Group. All Rights Reserved.
+ * Copyright (C) 2007, 2008 BEHR Software Systems. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  - Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  - Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *  - Neither the name of the BEHR Software Systems nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package   php-reader
+ */
+
+/**#@+ @ignore */
+require_once("ReaderException.php");
+require_once("Transform.php");
+/**#@-*/
+
+/**
+ * The Reader class encapsulates a file. It is hence responsible of upkeeping
+ * the connection to the file, keeping track of the cursor position and reading
+ * data from it.
+ * 
+ * @package   php-reader
+ * @author    Sven Vollbehr <sven.vollbehr@behrss.eu>
+ * @copyright 2006, 2007 The Bearpaw Project Work Group
+ * @copyright 2007, 2008 BEHR Software Systems
+ * @version   $Rev$
+ */
+class Reader
+{
+  /**
+   * @var resource The underlying file descriptor.
+   */
+  private $_fd;
+  
+  /**
+   * @var integer  The file size.
+   */
+  private $_size;
+  
+  /**
+   * Opens the file given as a parameter.
+   * 
+   * @param string $filename The absolute or relative path to the file.
+   * @throws ReaderException if the file cannot be read.
+   */
+  public function __construct($filename)
+  {
+    if (($this->_fd = fopen($filename, "rb")) === false)
+      throw new ReaderException("Unable to open file:" . $filename);
+    
+    fseek($this->_fd, 0, SEEK_END);
+    $this->_size = ftell($this->_fd);
+    fseek($this->_fd, 0);
+  }
+  
+  /**
+   * Closes the file.
+   */
+  public function __destruct()
+  {
+    @fclose($this->_fd);
+  }
+  
+  /**
+   * Checks whether there is more to be read in the file.
+   * 
+   * @return boolean Returns <var>true</var> if the end of the file has not yet
+   *         been reached; <var>false</var> otherwise.
+   */
+  public function available()
+  {
+    return $this->getOffset() < $this->_size;
+  }
+  
+  /**
+   * Jumps <var>size</var> amount of bytes in the file stream.
+   * 
+   * @return void
+   * @throws ReaderException if <var>size</var> attribute is not greater or
+   *         equal than zero.
+   */
+  public function skip($size)
+  {
+    if ($size < 0)
+      throw new ReaderException("Invalid argument");
+    fseek($this->_fd, $size, SEEK_CUR);
+  }
+  
+  /**
+   * Reads <var>length</var> amount of bytes from the file stream.
+   * 
+   * @return string Returns read bytes as a string
+   * @throws ReaderException if <var>length</var> attribute is not greater than
+   *         zero.
+   */
+  public function read($length)
+  {
+    if ($length <= 0)
+      throw new ReaderException("Invalid argument");
+    return fread($this->_fd, $length);
+  }
+  
+  /**
+   * Returns the current point of operation.
+   * 
+   * @return integer Returns the current cursor position.
+   */
+  public function getOffset()
+  {
+    return ftell($this->_fd);
+  }
+
+  /**
+   * Sets the point of operation, ie the cursor offset value.
+   * 
+   * @return void
+   */
+  public function setOffset($offset)
+  {
+    fseek($this->_fd, $offset);
+  }
+  
+  /**
+   * Returns the file size in bytes.
+   * 
+   * @return integer Returns the file size in bytes.
+   */
+  public function getSize()
+  {
+    return $this->_size;
+  }
+
+  /**
+   * Magic function to delegate the call to helper methods of Transform class
+   * to transform read data in another format.
+   *
+   * The read data length is determined from the helper method name. For methods
+   * where arbitrary data lengths are accepted a parameter can be used to
+   * specify the length.
+   *
+   * @param string $method The method to be called.
+   * @param string $params The parameters should the function accept them.
+   * @return mixed
+   * @throws ReaderException if no such transformer is implemented
+   */
+  public function __call($method, $params) {
+    $chunks = array();
+    if (preg_match
+          ("/get([a-z]{3,6})?(\d{1,2})?(?:LE|BE)?/i", $method, $chunks) &&
+        method_exists("Transform", $method)) {
+      return call_user_func
+        (array("Transform", $method),
+         $this->read(preg_match("/String|(?:H|L)Hex/", $chunks[1]) ?
+                     (isset($params[0]) ? $params[0] : 1) :
+                     ($chunks[1] == "GUID" ? 16 : $chunks[2] / 8)));
+    } else throw new ReaderException("Unknown method: " . $method);
+  }
+}